Pressure block



C. G. OLSON PRESSURE BLOCK Filed May 31, 1923 Patented May 5, 1925.

1,536,916 UNITED STATES PATENTOFFI'CE.

CARL G. OLSON, OF CHICAGO, ILLINOIS, ASSIGNOR TO ILLINOIS TOOL WORKS, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

PRESSURE BLOCK.

Application filed May 31,

To all whom it may concern:

Be it known that I, CARL G. OLSON, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new anduseful Improvement in Pressure Blocks, of which the following is a specification.

My invention relates to pressure blocks for printing presses, and the object is to provide means for checking thespacing betweenthe table and theprinting roller under the same conditions as exist. when the machine is operating; In the operation of printing presses it is essential that the spacing between the roller and the table of the machine shall be accurate and uniform across the entire width of the table while the printing is taking place. The space should be equal to, the height of the type plus the thickness of suitable covering on the metal roller for cushioning. In order to check the spacing between the table and roller under the same conditions as exist when the press is in operation it is necessary to check the measurements while there is being exerted between the roller andthe table a pressure approximately equal to the printing pressure. My purpose is to provide pressure blocks which may be placed on the table and caused to pass under the roller under the same conditions that will exist during printing, thus enabling the operator to check the measurements under operating conditions.

To test a printingmachine with my blocks a number of the blocks are placed in a straight line crosswise of. the table and at a definitedistance apart. The table is then advanced until the blocks come directly beneath the roller. The springs within the block are so selected and arranged that when the parts are in this position the pressure exerted will be substantially equal to the pressure which it is intended sliall be exerted by the type upon the paper during the final printing operation.

According to common practice printing pressure varies between 50 and 150 lbs. per linear inch of the roller, the amount depending upon the character of work to be done. To illustrate the operation of my blocks let it be assumed that the pressure is to be 100 lbs. per linear inch of the length of the roller. A suitable test may be made by placing the blocks in transverse alinement spaced 4 1923. Serial No. 642,486.

inches apart and capable of exerting 400 lbs. per block when the distance between the roller and the table is equal to the height of the type plus the thickness of the padding or cushion which is used during the printing operation. This is usually .987 inches. Under these conditions when the blocks rest upon the table and are moved to printing position (that is, the point where the roller comesclosest to the table), the operator will measure the distance between the table and the roller by a suitable gauge between each of the blocks. This gauging shows the con dition of the machine in one position, that is, it shows whether the various'portions of the table at this particular cross section will hold the type at the correct height when subjected to the action of the printing roller. This procedure is then repeated in other positions on the table until the entire surface of the table has been checked. The roller itself is massive and rotates in place, and is presumed to be rigid. The table is movable and cannot well be built so rigidly but by employing the blocks in the manner described the entire surface of the table as well as the condition of the roller itself may be readily and accurately checked.

I accomplish my object by the mechanism illustrated in the accompanying drawings, in which s Figure 1 is a cross sectional elevation of the principal portions of a printing press with a row of my pressure blocks in positions of use. The printing roller and table supporting roller and some of the other parts are shown in full instead of in section.

Figure 9. is an elevation chiefly in diametral,section of a pressure block embodying my invention.

Figure 3 is-a top plan View of the block, a portion of. the top of the housing being broken away to reveal the parts beneath.

Figure 4 is an elevation chiefly in diametral section of thepressure block in which the springs are nested instead "of opposed in .pairs as in Figure 2.

Like numerals denote like parts through out the several views.

In Figure 1 I have illustrated more or less conventionally the principal elements of a printing press with which my pressure blocks are most intimately concerned. In the form illustrated the table 1 reciorocates upon and is supported by a roller 2 which is journaled in blocks 3, which are slidable in vertical ways 4. The position of the blocks in the ways is determined by set screws 6 supported in brackets S on the main frame 10. The printing roller 12 is journaled in bearings 1% supported by brackets 16 rising from the main frame. It may be rotated in any suitable manner, for example, by a manually operated crank 18. In order that the printing roller and table shall operate in synehronism they are geared to gcther, the table having a rack 20 which meshes with a gear 22 on the roller. it will be understood that the printing press itself is no part of my invention and that a press is here illustrated merely to help explain the principle of operation and use of my invention.

Referring now especially to Figures 2 and 3 wherein a pressure block embodying my invention is illustrated: a chambered housing 2% is closed at the bottom by a bottom plate 26 which is screwed or otherwise fastened in place. 'The top of the housing has a circular central opening 28 which forms a guide for the upper end of a plunger 30. The bottom plate has a central circular opening 32 which forms a guide for the lower end of stem of the plunger. The plunger makes a fairly close sliding it so as to avoid lateral play so far as practicable. A collar 3% is formed near the upper end of the plunger and forms a stop to engage the under side of the top of the housing and limit the upward movement of the plunger. The parts are so proportioned that when the plunger is in uppermost position, its top surface will be somewhat above the top surface of the housing. The collar is normally held in contact by springs within the housing, one arrangement of the springs being shown in Figure 2 and another arrangement in Figure 4.

In both of the illustrated cases the springs are dished steel discs 36 having a central aperture for freely accommodating the stem of the plunger and having a diameter somewhat less than the internal diameter of the housing. In l igure 2 four discs are shown and they are arranged oppositely in pairs, the concave sides of each pair facing each other. In Figure 4 seven of these discs are shown and they are nested. In either case the number and arrangement of the springs will be selected in accordance with the amount of pressure which they are to exert when they are compressed under the actionof the printing roller 12. It is desirable to provide an insert 38 of lead or other comparatively soft metal to afford a marker in which the figures may be impressed to indiate the amount of pressure to which the block has been calibrated.

Operation: In assembling, the springs are so selected and arranged that they will be under a certain amount of initial tension and will thus force the plunger upward with the Ila ge 3 t in contact with the housing. This ini ial tension will be somewhat less than the tension to which the block has been calibrated when compressed to the predetcr mined spacing (for example .987 inches). In other words, the springs will exert an initial tension, but the final tension. when the plunger is type high plus the thickness of the padding to be used will be 4-00 lbs. or whatever other amount of pressure has been predetermined upon. If the printing pressure is to be lbs. per inch and the blocks are to be spaced inches apart each pressure locl: when the top of the plunger has been depressed to type height plus the padding will evert a pressure of 400 lbs. upon the table. The pressure blocks are used 011 the roller direct (the padding which is usually .071 inches thick, being absent during the test).

When the parts of the pressure block have been assembled in the manner described and the printing press is to be tested a set of blocks will be arranged in transverse alinement upon the table as indicated in Figure 1. The blocks will be properly spaced apart and the table will be moved until the row of blocits is directly beneath the roller. This gives maximum compression upon the plunger-s. The pressure blocks will thereupon cxcrt their calibrated pressure upon the table and the operator can then check the measurements to see whether the surface of the table is at a uniform height and at a proper distance below the roller. After the table has been checked it will be advanced to another similar row of blocks and the checking operation repeated. The result that these blocks afford a simple and accurate means for testing the conditions and adjustment of the press.

Having thus described my invention what I claim as new and desire to secure by Letter. Patent is:

1. A pressure block having a housing, a plunger slidable in said housing and a circular dished spring surrounding the plunger and encased within the housing for exerting a predetermined resistance when compressed a predetermined amount.

2. A device of the class described having a chambered housing, a plunger vertically slidable in said housing and having a stop for limiting the up 'ard movement, the upper surface of the plunger being above the upper surface of the housing when the plunger is in uppermost position, and a plurality of dished springs located within the housing and surrounding the plunger and being under tension when the plunger is in uppermost position.

5. A pressure block for testing printing presses, having a chambered housing closed at the top and bottom, a plunger fitting slidingly in the top and bottom of the housing, the plunger having a collar adapted to engage the under side of the top of the housing to limit the upward movement, the up per surface of the plunger being above the top of the housing when in uppermost position, and a plurality of spring members of circular outline adapted to be contained within the housing and to rest upon the bottom thereof, and normally hold the collar of the plunger in contact with the under side of the top of the'housing, said springs being apertured at the center for loosely accommodating the plunger.

4:. A. pressure block for testing printing presses having a ham ered housing closed at the top and bottom, a plunger fitting slidingly in the top and bottom of the housing, the plunger having a stop located within the l'iousing for limiting its upward movement, the upper end of the plunger normally projaeting above the top of the housing, and a plurality of calibrated dished spring washers surrounding the plunger within the housing for supporting said plunger.

In witness whereof I have hereunto subscribed my name.

- CARL Gr. OLSON. 

